The current art in generating power for transportation purposes basically utilize the internal combustion gas or diesel engine. The current art for electric power generation utilize gas turbines and/or steam turbines. These devices burn hydrocarbon fuels with air which contains (by weight) 23.1% oxygen, 75.6% nitrogen and the remaining 1.3% in other gases. The emissions resulting from the combustion of fuels for internal combustion engines (gasoline or diesel), with air contain the following pollutants that are considered damaging to our air environment. These smog causing pollutants, are: total organic gases (TOG); reactive organic gases (ROG); carbon monoxide (CO); oxides of nitrogen (NOx); oxides of sulfur (SOx); and particulate matter (PM). Approximately one half of the total pollutants emitted by all sources of air pollution in California are generated by road vehicles (Emission Inventory 1991, State of California Air Resources Board, prepared January 1994). The major source of this vehicle pollution comes from passenger cars and light to medium duty trucks.
No near term solutions appear in sight to drastically reduce the vast amount of air pollutants emitted by the many millions of automobiles and trucks operating today. Based on the State of California Air Resources Board study, the average discharge per person in California of the air pollutants from mobile vehicles, monitored by this agency during 1991 and reported in 1994, was approximately 1.50 lb/day per person. With a nationwide population of over 250,000,000 people, this data extrapolates to over 180,000 tons of air borne emissions per day being discharged in the USA by mobile vehicles. Also, the number of cars and miles that are being driven continue to increase, further hampering efforts to reduce smog causing pollutants.
Allowable emission thresholds are rapidly tightening by Federal and State mandates. These allowable emission reductions are placing severe demands on the transportation industry and the electric power generating industry to develop new and lower emission power systems.
Although considerable effort is being directed at improving the range of electric zero emission vehicles (ZEV) by developing higher energy capacity, lower cost storage batteries, the emission problem is been transferred from the vehicle to the electric power generating plant, which is also being Federally mandated (Clean Air Act Amendments of 1990) to reduce the same air toxic emissions as those specified for automobiles and trucks.
The current world wide art of generating power for consumers of electricity depends primarily on fossil fuel burning engines. These engines burn hydrocarbon fuels with air. As described above, combustion of fossil fuels with air usually produce combustion products that contain a number of pollutants. Current Unites States regulatory requirements prescribe the amounts of the atmospheric pollutants permitted in particular locations. Allowable pollutant thresholds are decreasing over time and thereby putting more and more pressure on industry to find better solutions to reduce these emissions of pollutants in the electric power generating industry and other power generating industries.
Other energy sources being developed to solve the emissions problem, by exploiting non combustible energy sources include fuel cells and solar cells. Developers are solving many of the technological and economic problems of these alternate sources. However, widespread use of these energy sources for vehicles and for electric power generating facilities do not appear to yet be practical.
In addition to the emission of pollutants, combustion based power generation systems also generate significant amounts of carbon dioxide (CO2). While CO2 emissions are currently not regulated in the United States, concern has been voiced by experts over the release of CO2 and other greenhouse gases into the environment. One method for eliminating the formation of CO2 in combustion based power generation systems is to utilize hydrogen as the fuel rather than a hydrocarbon fuel. Use of hydrogen as a fuel has many drawbacks including the highly flammable and potentially explosive nature of hydrogen when in a gaseous state, the significant energy required to maintain hydrogen in a liquid state, the low density of hydrogen requiring large volumetric storage capacity and the fact that all present commercial production of hydrogen comes from fossil fuels which also yield CO2 as a by-product.
Some attention has recently been given to the concept of separating the CO2 from other combustion products and then disposing of the CO2 by injecting it into deep porous geological formations or deep into the earth's oceans where environmental impacts of the release of the CO2 would be minimized. Interest in such terrestrial formation disposal techniques is exemplified by the recent issuance by the United States Department of Energy of a Small Business Innovation Research (SBIR) program solicitation (reference number DOE/ER-0706, closing date Mar. 2, 1998) specifically seeking strategies for mitigation of greenhouse gases and pollutants including CO2. This solicitation sought approaches to CO2 disposal involving usage of potential storage sites such as oil and gas reservoirs, unmineable coal seams, the deep ocean, or deep confined aquifers. CO2 separation and injection systems are known in the prior art but the CO2 is only partially separated and the processes are so energy intensive that such systems are not generally commercially viable. Accordingly, a need exists for such a more efficient CO2 separation and injection system which can sequester and dispose of the CO2 in an economically viable manner.